Europe's top court ruled that Google Inc. can be forced to erase links to content about individuals on the Web, a surprise decision that could disrupt search-engine operators and shift the balance between online privacy and free speech across Europe.

Under Tuesday's ruling—which doesn't trigger any specific new enforcement, but sets a strong legal precedent across the European Union—individuals can request that search engines remove links to news articles, court judgments and other documents in search results for their...